This section provides background information related to the present disclosure which is not necessarily prior art.
FIG. 1 is a view illustrating an example of the semiconductor light-emitting device (Lateral Chip) in the prior art, in which the semiconductor light-emitting device includes a substrate 100, and a buffer layer 200, a first semiconductor layer 300 having a first conductivity, an active layer 400 for generating light via electron-hole recombination and a second semiconductor layer 500 having a second conductivity different from the first conductivity, which are deposited over the substrate 100 in the order mentioned, and additionally, a light-transmitting conductive film 600 for current spreading, and an electrode 700 serving as a bonding pad are formed thereon, and an electrode 800 serving as a bonding pad is formed on an etched-exposed portion of the first semiconductor layer 300.
FIG. 2 is a view illustrating another example of the semiconductor light-emitting device (Flip Chip) in the prior art, in which the semiconductor light-emitting device includes a substrate 100, and a first semiconductor layer 300 having a first conductivity, an active layer 400 for generating light via electron-hole recombination and a second semiconductor layer 500 having a second conductivity different from the first conductivity, which are deposited over the substrate 100 in the order mentioned, and additionally, three-layered electrode films for reflecting light towards the substrate 100, i.e., an electrode film 901, an electrode film 902 and an electrode film 903 are formed thereon, and an electrode 800 serving as a bonding pad is formed on an etched-exposed portion of the first semiconductor layer 300.
FIG. 3 is a view illustrating still another example of the semiconductor light-emitting device (Vertical Chip) in the prior art, in which the semiconductor light-emitting device includes a first semiconductor layer 300 having a first conductivity, an active layer 400 for generating light via electron-hole recombination and a second semiconductor layer 500 having a second conductivity different from the first conductivity, which are deposited in the order mentioned, and additionally, a metallic reflective film 910 for reflecting light towards the first semiconductor layer 300 is formed on the second semiconductor layer 500, and an electrode 940 is formed on the side of a supporting substrate 930. The metallic reflective film 910 and the supporting substrate 930 are coupled together by a wafer bonding layer 920. An electrode 800 serving as a bonding pad is formed on the first semiconductor layer 300.
FIG. 4 is a view illustrating an example of the semiconductor light-emitting device described in U.S. Pat. No. 6,650,044, in which the semiconductor light-emitting device is of a flip chip type comprising a substrate 100, a first semiconductor layer 300 having a first conductivity, an active layer 400 for generating light via electron-hole recombination and a second semiconductor layer 500 having a second conductivity different from the first conductivity, which are deposited over the substrate 100 in the order mentioned, and additionally, a reflective film 950 for reflecting light towards the substrate 100 is formed on the second semiconductor layer 500, an electrode 800 serving as a bonding pad is formed on an etched-exposed portion of the first semiconductor layer 300, and an encapsulant 1000 adapted to enclose the substrate 100 and the semiconductor layers 300, 400 and 500. While the reflective film 950 can be composed of a metal layer as in FIG. 2, it can also be composed of an insulating reflective film, such as SiO2/TiO2 DBR (Distributed Bragg Reflector), as shown in FIG. 5. The semiconductor light-emitting device is mounted on a PCB (Printed Circuit Board) 1200 equipped with wiring 820, 960, by means of a conductive adhesive 830, 970. The encapsulant 1000 usually contains phosphor. As the semiconductor light-emitting device herein includes the encapsulant 1000, the other part of the semiconductor light-emitting device free of the encapsulant 1000 will be referred to as a semiconductor light-emitting device chip, for distinction.
FIG. 5 is a view illustrating yet another example of the semiconductor light-emitting device the prior art, in which the semiconductor light-emitting device includes a substrate 100, a buffer layer 200 growing on the substrate 100, an n-type semiconductor layer 300 growing on the buffer layer 200, an active layer 400 growing on the n-type semiconductor layer 300, a p-type semiconductor layer 500 growing on the active layer 400, a transparent conductive film 600 formed on the p-type semiconductor layer 500 for current-spreading, a p-side bonding pad 700 formed on the transparent conductive film 600, and an n-side bonding pad 800 formed on an etched-exposed portion of the n-type semiconductor layer 300. Moreover, a DBR 900 and a metallic reflective film 904 are formed on the transparent conductive film 600.
FIG. 13 is a view illustrating an example of the semiconductor light-emitting device proposed in JPA 2009-164423. In the semiconductor light-emitting device, a DBR 900 and a metallic reflective film 904 are provided on a plurality of semiconductor layers 300, 400 and 500, a phosphor 1000 is disposed opposite thereto. The metallic reflective film 904 and an n-side bonding pad 800 are electrically connected to external electrodes 1100 and 1200. The external electrodes 1100 and 1200 can be lead frames for a package, or electrical patterns provided on the COB (Chip on Board) or PCB (Printed Circuit Board). The phosphor 1000 can be coated conformally, or can be mixed with an epoxy resin and then used to cover the external electrodes 1100 and 1200. The phosphor 1000 absorbs light that is generated in the active layer, and converts this light to a light of longer or shorter wavelength.